low blow vs abuse

low blow and abuse both are nouns.

Word	Noun	Adjective	Verb	Adverb
low blow	Yes	No	No	No
abuse	Yes	No	Yes	No

As nouns, abuse is a hypernym of low blow; that is, abuse is a word with a broader meaning than low blow:

Other hypernyms of low blow include contumely, insult, revilement, vilification.

low blow (noun)	abuse (noun)
unscrupulous abuse	improper or excessive use
	cruel or inhumane treatment
	a rude expression intended to offend or hurt

low blow (verb)	abuse (verb)
	change the inherent purpose or function of something
	use wrongly or improperly or excessively
	use foul or abusive language towards
	treat badly